Gene networks involved in iron acquisition strategies in plants

Abstract

-Iron uptake is strictly controlled in all organisms. Iron deficiency induces a well-defined series of physiological events, either based on iron reduction (strategy I, dicots and monots except grasses) or iron chelation (strategy II, grasses). Genes encoding the structural components of the strategies I and II have been described recently using molecular, genetic and biochemical techniques. The major participants of the strategy I are the ferric reductase and the Fe II transporter encoded by Atfro2 and Atirt1 homologs, respectively. The strategy II comprises the enzymes for phytosiderophore biosynthesis encoded by the genes for nicotianamine synthase, nicotianamine aminotransferase and others. Transcriptional and post-transcriptional regulatory mechanisms control the strategy I and II genes. The tomato fer gene is among the first identified regulator genes for iron uptake. The identification and characterisation of the regulatory mechanisms is an important step towards designing new strategies for improving the iron content of crop plants for human health. iron uptake / strategy I genes / strategy II genes / regulation / fer Résumé -Les réseaux de gènes impliqués dans les stratégies d'absorption de fer par les plantes. L'absorption de fer est contrôlée de manière rigoureuse dans tous les organismes. La carence en fer entraîne des séries bien connues d'incidents physiologiques, qu'ils soient basés sur la réduction de fer (stratégie I, dicotylédones et monocotylédones à l'exception des plantes herbacées) ou la chélation de fer (stratégie II, plantes herbacées). Les gènes codant pour les composants structuraux des stratégies I et II ont été décrits récemment en utilisant des techniques moléculaires, génétiques et biochimiques. Les principaux participants de la stratégie I sont la réductase ferrique et le transporteur Fe II codés respectivement par les homologues de Atfro2 et Atirt1. La stratégie II comporte les enzymes pour la biosynthèse de phytosidérophore codées par les gènes de la nicotianamine synthase, de la nicotianamine aminotransférase et d'autres. Les mécanismes de régulation transcriptionels et post-transcriptionels contrôlent les gènes des stratégies I et II. Le gène fer de la tomate figure parmi les premiers gènes régulateurs pour l'absorption de fer à avoir été identifiés. L'identification et la caractérisation des mécanismes régulateurs est une avancée considérable pour envisager de nouvelles stratégies visant à améliorer le contenu en fer des plantes cultivées pour la santé humaine. absorption de fer / stratégie I gènes / stratégie II gènes / régulation / fer

The mutual responses of higher plants to environment: Physiological and microbiological aspects

“…Mycorrhizal fungal community plays an important role in soil environment quality and natural circle, also influencing higher plant functions to a large extent [6,7,[127][128][129][130][131][132][133][134]. Our understanding of the controls on mycorrhizal fungal species distribution and community organization is in its early childhood, especially when compared with that of the more mature fields of plant and animal community ecology and biogeography.…”

“…Plants live in soil-plant-atmosphere continuum (SPAC) environment, and they have to coordinate the mechanisms of diverse types to respond to the above changing environment at any time for sustainable survival [4][5][6][7][8][9][21][22][23][24][25][26][27][28][29][47][48][49][50][51][52][53][54][55][56][57][58][59]. Plant production realization is obtained eventually through physiological pathways at least at the level of individual and community [102][103][104][105][106][107][108][109]120,[130][131][132][133][134][135][136][137][138][139][140].…”

“…Water deficits in soil environment also influence solute transport (ion and nutrient uptake of plants) to larger extent, which effects on photosynthetic reactions in plant chloroplasts in many ways [117,120,131,135,[139][140][141][142][143][144][145][146][147]. This is the reason that ion homeostasis and redox state have been brought to attention [4][5][6][7][21][22][23][24][25][26][27][28][29][111][112][113][114][115][116][117][118][119]. The series of the above reactions and processes occurring at different soil-root biointerfaces is regulated and controlled by plant gene regulatory network system spatially and temporally on the basis of responding to plant developmental cues, through which plants can elegantly respond to the changing environment [8][9][10][11][12][13][14][15][16][17]…”

“…Physiological and microbiological responses of higher plants to environment have been studied extensively over the world, especially by targeting model plants and crop plants [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Abiotic stresses in environment are linked with all the living process of higher plants and greatly influence plant productivity developmental cues and environmental stimuli, most of which are the important factors affecting eco-environment such as low temperature, drought, salinity and UV-B radiation, which often occur in terrestrial ecosystem.…”

“…In the discipline context, it is very interesting to understand the interaction between plants and their environment. It is also a urgent need for human life that we should create crop plants that are able to confront successfully unfavorable natural conditions [7,10,11,[128][129][130][131][132][133][134]144]. The main aim in plant breeding is to obtain plants that combine higher yields, reliable yield stability, better quality and obvious characters resisting stresses (abiotic and biotic) over years and locations [15,16,22,36].…”